Sewing machine



mMy l, 1947. E. N. SIMMONS 2,423,259

SEWING MACHINE Filed Jan. 1, 1945 2 Sheets-Sheet l YF/G. l .54 2l l a-Tfj 33 w 35 INVENTOR.` I4 EDWARD N. 'SIMMONS 5 v BYW-ZZQALM ATTORNEYS July 1, 1947. E. N. SIMMONSv SEWING MACHINE INVENTOR.

2 Sheets-Sheet 2 EDWARD N. SIMMONS Filed Jan. l, 1945 Patented July l, 1947 SEWING MACHINE Edward N. Simmons, Chicago, Ill., assignor to Simmons Manufacturing Co., Chicago, Ill., a corporation of Illinois Application January 1, 1945, Serial No. 570,884

9 Claims. l

This invention relates to sewing machines and particularly to power operated sewing machines having stop motion mechanism for terminating the operation thereof after the predetermined number of stitches.

Stop motion mechanisms are utilized on many kinds of sewing machines, such for example as button sewing machines, button hole-machines, and machines for performing certain kinds of tacking operations, and such stop motion mechanisms may be utilized either on hand operated machines or upon sewing machines that are power operated. Where such stop motion mechanisms have heretofore been applied to power driven sewing machines, such mechanisms have usually been quite complicated in character and have required that the mechanism be built into the frame oi the sewing machine so that the cost of such machines has been relatively high. It is therefore an important object of this invention to enable stop motion mechanism to be provided in a power operated sewing machine in such a manner that the cost will be relatively low. Another and related object is to provide stop motion mechanism that is simple and rugged in character and which may be applied to a sewing machine in a simple and expeditious manner.

A further object of the invention is to provide a power driving means for sewing machines that includes a drive shaft, clutch mechanism and stop mechanism adapted to be associated with a sewing machine externally of the frame of the sewing machine, and a further object is ,to provide such a mechanism that is adapted to be readily associated with the sewing machine so as to eiect stopping of the sewing machine after a predetermined number of stitches have been made.

Other and further objects of the present invention will be apparent from the following description and claims are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment and the principle thereof and what I now consider to be the best mode in which I have contemplated applying that principle. Other embodiments of the invention embodying the same or equivalent principle may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

Fig. l is a fragmental side elevational view of a sewing machine having driving means and stop mechanism embodying the features of the invention;

Fig. 2 is a fragmental plan view taken partially in section along the line 2-2 of Fig. 1;

Fig. 3 is a rear elevational view of the machine taken partially in section along the line 3--3 of Fig. 1;

Fig. 4 is a fragmental side elevational view of the machine as viewed from the line 4--4 of Fig. 3, that portion of the casing being broken away to show internal details of the machine;

Fig. 5 is a iragmental view taken partially in section and showing the details of the stop mechanism; and

Fig. 6 is a fragmental sectional view illustrating details of the clutch mechanism and the stop mechanism.

For purposes of disclosure the invention has been herein illustrated as embodied in a sewing machine I0 having a, hollow base II mounted on a frame or pedestal I2 and arranged to be driven through a driving clutch I3 by a motor I4 that is also mounted on the pedestal I2 rearwardly of the base I I of the sewing machine. The sewing machine I as herein shown is a relatively small machine adapted to perform tacking and like operations and operating to produce a chain stitch. The base II has a rigid and forwardly projecting knee I 6 having a work supporting plate I'I mounted thereon in a horizontal position, and at the rear end of the work supporting plate I 1, the bed I I has an upstanding column I8, from the upper end of which a rigid arm I9 projects so as to support a head 20 immediately above the forward end of the work supporting plate II. The head 2l) has a needle bar 2| mounted for vertical reciprocation therein and an eye-pointed needle 22 mounted in the needle bar 2| is arranged for cooperation with a rotary chain stitch looper 23 that is mounted beneath an opening 24 in the work supporting plate II. The looper 23 is housed within a tiltable housing 25, and it is carried on the forward end of a horizontal looper shaft 26 that is mounted within the frame I I so as to project forwardly through the knee I6. At its rear end the looper shaft; 26 projects into a recess 21 formed in the rear wall of the base, and within this recess the shaft 26 has a. gear 28 fixed thereon by means such as a set screw 29.

that is fixed eocentrically in the outer face of the gear 28, and this link 30 extends in an upward direction Within a slot 21A in the rear face of the column I8 and is connected at its upper end to the end of an arm 32. The arm 32 is xed on a rock shaft 33 disposed within a horizontal groove 34 in the arm I9, and at its forward end the rock shaft 33 is connected by means including an arm 35 to the needle bar 2| so as to effect reciprocation of the needle bar in timed relation to the rotative movements of the looper shaft 26.-

The stitch forming mechanism that is thus afforded in the machine l is arranged to operate upon work that is clamped between the upper and lower clamps 38 and 39, the lower work clamp 39 being mounted on a slide plate 4I) that is guided for reciprocating movement in a front to rear direction on the work holding plate I'I of the machine. The upper work clamp 38 is fixed on the upper end of a column 4I provided on the slide plate 40, and means of a conventional character may be utilized for clamping and unclamping the upper work clamp 38. The slide plate 43 is reciprocated in timed relation to the operation of the stitching forming mechanism, and this is accomplished by means associated with a transverse shaft 43 mounted in the frame 'I l just below the looper shaft 26. The transverse shaft 43 is driven from the looper shaft 26 by helical gears 44 and 45 mounted respectively on the looper shaft 26 and the transverse shaft 43. The relationship of the gears 44 and 45 is such that the transverse shaft 43 is driven through one revolution for each two revolutions of the looper shaft 26, and the reciprocating means for the slide plate 40 are therefore arranged so that the slide plate will be operated through one complete reciprocation each time the shaft 43 is rotated through a full revolution. The reciprocating means as herein shown comprise a single lobe cam 4l fixed on the lshaft 43 and disposed between bifurcations llt-.formed in the lower end of a rocking lever 49. The rocking lever 49 is pivoted on the frame II somewhat above the shaft 43, and the upper end of the rocking lever 49 extends through the plate Il 'and has a link 5I 'pivoted thereto at 52, the other end of the link being pivoted at 53 on the column 4I. Thus the work holder is reciproeated through a complete cycle each time the shaft 43 is rotated. The thread for the stitch forming operations may be provided from a spool 54 mounted at the top of the column I8 and the thread may be led through suitable guides and tensioning devices to the needle 22 in a conventional manner.

In accordance with the present invention, the drive mechanism VI3 is constructed and arranged as a separate unit that may readily be associated with the machine or may be readily removed for replacement or repair. Thus a mounting bracket 33 is provided, this :bracket being in the form of an elongated bar adapted t0 have one end thereof secured against the side of the bed Il by means such as a screw 6I, and the bar of the bracket has a pair of parallel arms 62 and 33 formed thereon so as to project laterally therefrom vin spaced relation to serve as a mounting means for various elements of the clutch mechanism and stop mechanism. The arm 62, as shown in Figs. l and' 2, is arranged to bear against the rear end of the frame II, and may be secured thereto by means such as .a lcap screw 64. The spaced arms 62 and 63 serve to afford bearings lfor a 'drive kshaft '6'5 that is supported therein so as to be parallel to the looper shaft 26, and one end of the drive shaft B5 extends be yond the arm 62 and into the recess 21 beneath the gear 28, and a pinion 6G fixed on this projecting end of the shaft 63 is meshed with the gear 28 so that rotation of the shaft 65 serves to drive the looper shaft 25 and the mechanism that is operated in timed relation thereto.

The drive from the motor I4 to the drive shaft E55V includes a clutch 'I3 having a driven member Il lixed on the shaft 65 and having a driving member 'l2 freely rotatable upon the shaft 55. The driving member 12 of the clutch is in the present instance in the form of a gear that is meshed with a relatively wide pinion 13 that is secured by means of a coupling 'I4 on the shaft of the motor I4. The clutch members Il and 'I2 are illustrated in Figs. l and 2 in their disengaged positions, and it will be observed that these members have driving lugs or pins 'I5 and T5 projected respectively from their adjacent surfaces so that by movement of the driving member I2Y axially along the shaft 65 and toward the driven member Il, the clutch may be engaged by causing the pin 'I3 to engage the pin 15 on the driven member 1I of the clutch. A single driving pin of the aforesaid character is provided on each of the two clutch members 'Il and l2 so that the clutch has a single position of driving engagement. Shifting movements may be imparted to the driving member l2 of the clutch by means of the shifting fork 'l1 that is engaged with a suitable groove in the hub of the driving member 12, and the shiftingl fork 11 is in the present case mounted on a control member 'I8 that is slidable longitudinally along the top of the bracket 6D parallel to the axis of the shaft 6'5. In the present instance the control member I8 has a plurality of slots 'I9 formed therein, and guiding studs 8D are extended through these slots 'IIBA and into the bracket 64 so as to guide the control member 'I8 for shift ing movement. The mounting of the shifting fork 'Il on the control member 'I8 is afforded by an arm 8| that is extended laterally from the control member 18 to a point overlying the axis of the shaft 65, the fork 'I1 being fixed on the arm 8| so as to depend from one edge thereof. Thus by longitudinal shifting movement of the control member 18, the clutch element 'I2 may be engaged or disengaged.

The control member 'I8 -is normally urged in a right-hand direction as viewed in Figs. 1 and 2, thereby to normally urge the clutch member 12 toward a disengaged relationship, and in the present instance, at least a portion of this yielding force is afforded by spring means that also serve to actuate the stop plunger that stops the mechanism with the needle bar 2I in its upper or withdrawn position. This stop mechanism operates upon the driven member 1I of the clutch, and as Will be evident in Figs. 2, 5 and 6, the stop mechanism includes a stop plunger 83 mounted for longitudinal reciprocating movement in a mounting sleeve 84, this mounting sleeve 84 being supported in the arm 63 of the bracket 60 so that the end of the plunger 83 may be projected outwardly from the sleeve 84 and into engagement with an adjacent side surface 'IIA of the driven clutch member 1I, The plunger 83 is urged longitudinally toward engagement with the surface 'IIA of the member by a spring 85 housed within the sleeve 84, and when the plunger 83 is thus moved with a yielding force into engagement with the face 'IIA of the driven member 1I, the plunger 83 will be in position to enter and engage with a recess 86 for-med in the surface 1|A. This recess 86 is arranged with a sloping surface 81 entering into its leading edge and along which the plunger 83 may ride longitudinally into the recess 86, and when the plunger 83 has partially entered the recess, the continued movement of the driven member 1| in the direction indicated'by the arrow in Fig. 5 causes a yielding abutment 88 on the member 1| to engage with the side edge of the plunger 83. The yielding abutment 88 is in the form of a headed pin that is mounted on a spring 89 within the member 1|, and the head of this member is arranged to form the trailing edge of the slot or recess 88. Thus the abutment of the pin 88 with the plunger 83 stops the driven member 1| in a particular rotative position, and the plunger 83 thereupon moves further into the recess 86 so as to be engaged not only with the trailing edge of the recess as afforded by the abutment 88, but also with an abrupt leading side surface 86A of the recess 86. Thus the plunger 83 will serve to hold the driven member 1| in a particular rotative position.

The engagement and disengagement of the stop plunger 83 is controlled by the yoperation of the control member 18, and this is attained by an arm 92 Xed on the control member 18 so as to project over the top of the plunger 83, and a pin 93 xe'd in the plunger 83 is extended upwardly through a longitudinal slot in the mounting sleeve 84 and through an opening in the arm 92. Thus the force of the spring 85 acts through the plunger 83, the pin 93 and the arm 92 to urge the control member 18 in such a direction as to tend to open or disengage the clutch 19.

It will be evident, however, that when the control member 18 is moved rearwardly, or to the left as viewed in Figs. 1 and 2, the stop plunger 83 will be moved in an disengaging direction, and the driving member 12 of the clutch will be moved in an engaging direction, and such movement may be imparted to the control member 18 by an operating or starting handle 95 that is mounted on one side of the frame so as to be conveniently accessible to the operator of the machine. The starting handle 95 is in the form of a bell crank that is pivoted at 96 on the side of the frame Il, and the bell crank has a downwardly A projecting arm 96A, the rounded lower end 96B of which is disposed in a slot in a bracket 91 Xed on the top of the control member 18. The arm 96A in the present case has a spring 88 connected thereto and extended in a forward direction, as will be evident in Fig. 4, the spring being anchored at 98A on the machine frame. The spring 98 thus serves to urge the control member 18 in a forward direction, and the spring 99 therefore cooperates with the spring 85 in urging the control member 18 in a clutch-opening direction. When the machine is to be started through an operating cycle, the starting handle 95 is 'depressed, thereby to move the control member 18 in a rearward direction so as to release the stop plunger 83 and eifect operative engagement of the driving member 12 with the driven member 1|. When the control member 18 is thus moved toward its clutch-engaging position, it is latched in this position by a latch member |90 that is pivoted intermediate its ends on a screw |0| xed in the forward end of the mounting bracket 69, and this latch has its upper end |09A arranged to ride against the side of the control member 18 as shown in Figs. 2 and 3 when the latch is released. An expansive coil spring |92 acting between the lower end of the latch and the machine frame, as shown in Fig. 3 of the drawings, urges the latch |00 toward its effective or latching position that is indicated in dotted outline in Fig. 3, this eiective position being limited and determined by a stop screw |03 mounted in the upper end of the latch |00 iso as to engage the side wall of the machine when the latch |09 has reached the desired position. Thus it will be clear that when the starting lever is depressed so as to move the control member 18 in a rearward direction, the latch |00 will spring into the effective position that is shown in full lines in Fig. 6, and in dotted outline in Fig, 3.

The clutch 10 will, of course, be maintained in its engaged relationship until such time as the latch |90 is released, and in accordance with the present invention this releasing action takes place when the machine has performed the desired number of stitching operations. The release mechanism includes a push rod |05 mounted for transverse sliding movement in the machine frame so that one end of the push rod may be engaged with the upper end portion of the latch |90 to move the latch to its released position. The other end of the push rod |95 is arranged so as to be located in the path of a cam |06 that becomes effective when the desired number of stitches have been completed. This cam |98 is, in the present instance, xed on a gear |91 mounted on one end of a transverse shaft |08, and the gear |01 is meshed with a gear |09 fixed on one end of the shaft 43. The relationship of the gears |01 and |09 therefore determines the numberl of stitches that are to be performed under control of the stop motion. In the present instance it will be recalled that the shaft 43 makes one revolution for each two revolutions of the looper shaft 28, and the present embodiment of the invention is designed to render the stop motion effective to stop the machine after six stitches have been made. For this reason the gears |01 and |09 bear a threeto-one relationship, so that the gear |01 makes a complete revolution while the stitch forming mechanism is making six stitches. When six stitches have thus been formed, the cam |06 moves into engagement with the adjacent end of the push rod |95, as will be evident in Fig. 3 of the drawings, and the push rod |95 is thereby moved to the left as viewed in Fig. 3 to effect release of the latch |99. When this occurs, the control member 18 is released and is moved in a forward direction by the resilient forces applied by the springs 85 and 98. Such forward movement of the control member 18 is of course limited by the engagement of the end of the plunger 83 with Vflat portions of the surface 1|A of the driven member 1|, and this relationship is such that the two driving pins 15 and 16 are maintained at this time in a slight overlapping or engaged relationship, thereby to continue the drive between the two members of the clutch. However, when the plunger 83 starts its movement in an endwise direction and along the sloping surface 81, Fig. 5 the disengaging movement of the clutch pins 15 and 18 is continued, and at about the time when the plunger 83 is aligned with the recess 86, the disengagement of the pins 15 and 16 is completed. The stop plunger 83 is then free to act as a positive stop, and after the side of the plunger 83 has been engaged by the resilient abutment 88, the endwise movement of the plunger 83 is completed so that the opposing action of the abutments 86A and 8B serves to hold the driven member 'Il in a predetermined angular or rotative position.

The relationship of the gearing is, of course, arranged so that when the stop plunger 83'is engaged with the recess 88 by reason of. the action of the cam |236 and the push rod |5, the needle bar 2| will be in its uppermost position, thereby to be free of the work so that the workman may readily remove the completed work from the machine. In attaining this action, the ratio between the gears 66 and 28 is a one-to-two relationship, and while the needle bar 2| might be stopped in its lowermost position by engagement of the stop plunger 83 with the recess 86 in alternate cycles of rotation of the shaft 65, the location of the cam |06 on the gear |61 is such that the rod |li is engaged and actuated during a rotative cycle of the shaft B5 wherein the needle bar 2| is being moved an upward direction, and therefore when the plunger 83 becomes eiTective, the needle bar 2l is in its upper position,

From the foregoing description it will be evident that the present invention enables stop motion mechanism to be incorporated in power driven sewing machines in a simple and expeditious manner, and it will also be apparent that the driving mechanism and the stop means may under the present invention be constructed as a unit that may be readily and easily mounted in or removed from its operative association with the sewing machine. Moreover, it will be clear that those elements of the stop motion that are subjected to rough usage and wear are included in the removable unit so that problems of upkeep of the mechanism are materially simplified.

Thus, while I have illustrated and described the preferred embodiment of my invention, it is to be understood that this is capable of variation and modification and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

l. In a sewing machine having a main frame, stitch forming mechanism mounted on said frame, shiftable work clamping mechanism mounted on said frame and operable to shift the work with relation to the stitch forming mechanisms, means for operating said stitch forming mechanism and for shifting said shiftable work clamping mechanism including a main operating shaft mounted for rotation in said frame, means affording a drive for said operating shaft and including a mounting bracket secured on said frame, a drive shaft rotatively mounted in said bracket and drivingly connected to said operating shaft for driving the same when said drive shaft is rotated, driving and driven clutch elements mounted on said drive shaft, a motor operable to constantly rotate said driving clutch element, means fixing said driven clutch element on said drive shaft, means on said driven clutch element affording a stop shoulder, a stop plunger shiftably mounted on said bracket for movement into and out of engagement with said stop shoulder, said driving ciutch eiement being mounted for shifting movement on said drive shaft, a control member mounted on said bracket for shifting movement parallel to the axis of said drive shaft, means affording connections between said control member and said driving clutch element and between said control member and said stop plunger to shift said stop plunger to its released position and said driving clutch element to its engagingr position when said control member'is moved in one direction and to shift said driving clutch element to a disengaged position and to shift said stop plunger to effective position when said control member is shifted in the other direction, spring means urging said control member in said other direction, a latch operable to hold said control member against movement by said spring means to thereby maintain said clutch element in engagement, and means driven in timed relation to said operating shaft and operable after said stitch forming mechanism has formed predetermined number of stitches to release said latch and thereby disengage said clutch elements and render said stop plunger eiective.

2. In a sewing machine, a main frame, stitch forming mechanism mounted on said frame, means for operating said stitch forming mechanism including a horizontal operating shaft eX- tended longitudinally of the frame, said operating means including a gear disposed on the outside of said frame and nxed on the rear end of said operating shaft, work clamping and shifting means mounted on said main frame, means for reciprocating said work shifting means and including a transverse shaft driven from said operating shaft, a control shaft extended transversely through said frame and driven from said transverse shaft at a reduced speed, the driving connection between said transverse shaft and said control shaft including a gear mounted on said control shaft, a push rod extended through said frame and having one end disposed adjacent to said last mentioned gear, cam means on said last mentioned gear for actuating said push rod each time said control shaft is rotated through a complete revolution, driving means for said machine including a drive shaft having driving and driven clutch elements mounted thereon, a stop plunger engage-able with said driven clutch member to stop the same in a predetermined rotative position, a shiftable control member operatively associated with said driving clutch element and said stop plunger and having a clutch-engaging position wherein said clutch is engaged and said stop plunger is disengaged and having a clutch-disengaging position wherein said clutch is disengaged and said stop plunger is engaged, and a latch for holding said control member in a clutch-engaging position, said latch being disposed in the path of movement of said push rod whereby said latch is reieased by said push rod at the end of a complete revolution of said control shaft.

3. In a sewing machine, a main frame, stitchforming mechanism mounted on said frame, means for operating said stitch-forming mechanism including a horizontal operating shaft extended in a front to rear direction in said frame, said operating means including a gear disposed on the outside of said frame and fixed on the rear end of said operating shaft, work clamping' and shifting means mounted on said main frame, means driven from said operating shaft for reciprocating said work shifting means, a driving unit for said machine comprising a bracket detachably mounted in predetermined position on the exterior of said frame adjacent to said gear, a drive shaft mounted in said bracket and having a pinion thereon arranged to mesh with said gear when said bracket is mounted in said position on said frame, driving and driven clutch elements mounted on said drive shaft, a stop plunger mounted on said bracket and engageable with said driven clutch member to stop the same in a predetermined rotative position, a control member shiftably mounted on said bracket andY operatively associated with said driving clutch element and said stop plunger and having a clutch-engaging position wherein said clutch is engaged and said Astop plunger is disengaged and having a clutch-disengaging position wherein said clutch is disengaged and said stop plunger is engaged, a latch mounted on said bracket for holding said control member in clutch-engaging position, and governing means mounted on said frame and driven by said operating shaft and operable to disengage said latch after said stitch-forming mechanism has completed a predetermined number of stitches.

4. In a sewing machine, a. main frame, stitchforming mechanism mounted on said frame, means for operating said stitch-forming mechanism including an operating shaft mounted in said frame and a gear fixed on said operating shaft in a position wherein it is accessible from the exterior of said frame, work clamping and shifting means mounted on said main frame, means driven from said operating shaft for reciprocating said Work shifting means, a driving unit for said machine comprising a bracket detachably mounted in predetermined position on the exterior of said frame adjacent to said gear, a driveshaft mounted in said bracket and having a pinion thereon arranged to mesh with said gear when said bracket is mounted in said position on said frame, clutch means mounted on said drive shaft, stop means mounted on said bracket and operable to stop said drive shaft in a predetermined rotative position, a control member shiftably mounted on said bracket and operatively associated with said driving clutch and said stop means and having a clutch-engaging position wherein said clutch is engaged and said stop means are disengaged and having a clutch-disengaging position wherein said clutch is disengaged and said stop means are engaged, a latch mounted on said bracket for holding said control member in clutch-engaging position, and means mounted on said frame and driven by said operating shaft and operable to disengage said latch after said stitch-forming mechanism has completed a predetermined number of stitches.

5. In a sewing machine, a machine frame, stitch-forming mechanism mounted on said frame, shiftable work clamping means mounted on said frame, means for operating said stitchforming mechanism and said work clamping means and including an operating shaft mounted in said frame, and a gear fixed on said operating shaft, a driving unit for said machine comprising a bracket detachably mounted in predetermined position on said frame adjacent to said gear, a drive shaft mounted in said bracket and having a pinion thereon arranged to mesh with said gear when said bracket is mounted in said position on said frame, clutch means mounted on said drive shaft, stop means mounted on said bracket and operable to stop said drive shaft in a predetermined rotative position, a control member shiftably mounted on said bracket and operatively associated with said driving clutch and said stop means and having a clutch-engaging position wherein said clutch is engaged and said stop means are disengaged and having a clutch-disengaging position wherein said clutch is disengaged and said stop means are engaged, a latch mounted on said bracket for holding said control member in clutch-engaging position, manually operable means for shifting said control member to clutch-engaging position, and means mounted on said frame and driven by said operatving shaft and operable to disengage said latch after said stitch-forming mechanism has completed a predetermined number of stitches.

`6. In a sewing machine, a machine frame, stitch-forming mechanism and shiftable work holding means mounted on said frame, means for operating said stitch-forming mechanism and said Work holding means including an operating shaft mounted in said frame, and a gear fixed on said operating shaft, a driving unit for said machine comprising a bracket detachably mounted in predetermined position on the exterior of said frame adjacent to said gear, a drive shaft mounted in said bracket and having a pinion thereon arranged to mesh with said gear when said bracket is mounted in said position on said frame, clutch means mounted on said drive shaft, stop means mounted on said bracket and operable to stop said -drive shaft in a predetermined rotative position, a control member shiftably mounted on said bracket and operatively associated with said driving clutch and said stop means and having a clutch-engaging position wherein said clutch is engaged and said stop means are disengaged and having a clutch-disengaging position wherein said clutch is disengaged and said stop means are engaged, a latch mounted on said bracket for holding said control member in clutch-engaging position, a starting element mounted on said frame, means on said control member engageable by said starting element whereby said starting element may be operated to shift said control member to clutch engaging position, and latch-releasing means mounted on said frame in position to be operatively associated with said latch when said bracket is mounted in said position on said frame and driven by said operating shaft and operable to disengage said latch after said stitch-forming mechanism has completed a predetermined number of stitches.

7. In a sewing machine a main frame, stitchforming mechanism mounted on said frame, means for operating said stitch-forming mechanism including an operating shaft mounted in said frame, shiftable work holding means mounted on said main frame, means driven from said operating shaft for shifting said work holding means, a driving unit for said machine comprising a bracket detachably mounted in predetermined position on the exterior of said frame adjacent to said operating shaft, a drive shaft mounted in said bracket and having means thereon arranged to drivingly associate said drive shaft and said operating shaft when said bracket is mounted in said position on said frame, clutch means mounted on said drive shaft, stop means mounted on said bracket and operable to stop said drive shaft in a predetermined rotative position, a control member shiftably mounted on said bracket and operatively associated with said driving clutch and said stop means and having a clutch-engaging position wherein said clutch is engaged and said stop means are disengaged and having a clutch-disengaging position wherein said clutch is disengaged and said stop means are engaged, a latch mounted on said bracket for holding said control member in clutch-engaging position, and means mounted on said frame and driven by said operating shaft and operable to disengage said latch after said stitch-forming mechanism has completed a predetermined number of stitches.

8. A driving unit for a sewing machine comprising a bracket adapted to be detachably mounted in predetermined position on the exterior of the fra-me of such a sewing machine, a drive shaft mounted in said bracket and having apinion thereon arranged to mesh with an operatin-g gear of the machine when said bracket is mounted i-n said position on a sewing machine frame, driving and driven clutch elements mounted on said drive shaft, a stop plunger mounted von said bracket and engageable with said driven clutch member to stop the same in a predetermined rotative position, a control member shiftably mounted on said bracket and operatively associated with said driving clutch element and said stop plunger and having a clutch-engaging position wherein said clutch is engaged and said stop plunger is disengaged and having a clutchdisengaging position wherein said clutch is disengaged and said stop plunger is engaged, a spring means acting between said bracket and said control member to urge said control member toward said clutch-disengaging position, and a latch mounted on said bracket for holding said control member in clutch-engaging position.

9. A driving unit for a sewing machine comprising a bracket adapted to be detachably mounted in predetermined position on the exterior of the frame of such a sewing machine, a drive shaft mounted in said bracket and having means thereon for operatively connecting the shaft with the mechanism of the machine when said bracket is mounted in said position on a sewing machine frame, clutch means mounted on drive shaft, said stop means mounted in part on said bracket and in part on said shaft and being operable to stop said shaft in a predetermined rotative position, a control member shiftably mounted on said bracket and operatively associated with said clutch means and said stop means and having a clutch-engaging position wherein said clutch is engaged and said stop means are disengaged and having a clutch-disengaging position wherein said clutch is disengaged and said stop means are engaged, spring means urging said control member toward said clutch-disengaging position, and governing means mounted on said bracket for holding said control member in clutch-engaging position.

EDWARD N. SIMMONS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,351,486 Nunn Aug. 31, 1920 1,295,827 Murphy Feb. 25, 1919 766,814 Diehl Aug. 9, 1904 1,878,091 Allen et al Sept. 20, 1932 

